Automobiles, trucks, off-road equipment and engine driven machinery utilize air filters to remove air borne contaminants from engine intake air before the air is introduced for combustion. These filters are sealed in a housing to prevent air borne contaminants from bypassing the filter before the air enters directly into the engine. It is preferable that these filters be made with a filtration media that offers a combination of the highest level of filter efficiency possible, as well as the highest level of dirt holding capacity, which capacity is determinative of filter life.
One approach to significantly increasing filter capacity while marginally increasing efficiency is to add pre-cleaners. Pre-cleaners are currently made from either fibrous webs of textile media, polyester foam or poly-ether foam. To date, pre-cleaners have always had flat upstream faces which limits dirt carrying capacity and thus the life of the filter utilizing the pre-cleaner. This is because relatively large particles of dirt tend to clog the upstream face of the filter media, decreasing the efficiency of the filter media even when the primary filter is not clogged, due in part to the pre-cleaner removing the large particles. There is always a need to further increase the capacity of air filters so as to extend their efficiency and thereby extend their life because the result of even a slight increase in efficiency and filter life means that the fleets of vehicles and aggregate of machines utilizing an improvement contributes to cleaner air and lower fuel consumption generally. Such improvements, when combined with other improvements in reducing air pollution and fuel consumption, have a very large, positive effect on the environment and thus improve life quality.